Immune LAF1 mice will be treated with varying doses of antigen D-dGL conjugates to induce a suppression of a secondary IgE response. Antibody responses will be measured by radioimmunoassay (IgG) and passive cutaneous anaphylaxis (IgE). Lymphocyte transformation and adoptive transfer experiments will be performed to determine the site of action of antigen D-dGL suppression. Additional experiments will be focused upon the duration of suppression and the effect of multiple doses of antigen D-dGL upon additional antigen challenges of suppressed mice. Chemically modified antigen B will be used to study the induction and kinetics of suppressor T-cells. In vivo and adoptive transfer experiments to determine the duration of suppression achieved using the modified antigen B and the effects of multiple antigen challenges are anticipated. The experiments proposed will provide a rational basis for the use of antigen D-dGL conjugates and modified antigen B in timothy-sensitive rhesus monkeys and human patients.